System and method for protecting neurovascular structures

ABSTRACT

Devices and methods for protecting the neurovascular structures about the vertebral column are provided. One embodiment of the invention comprises a neuroprotective stent or device adapted for placement in an intervertebral foramen of a vertebral column and configured to resist compression or impingement from surrounding structures or forces. The stent or device may further comprise a flange or hinge region to facilitate attachment of the device to the vertebrae or to facilitate insertion of the device in the foramen, respectively.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. application Ser. No.15/591,550, filed on May 10, 2017, which is a continuation of U.S.application Ser. No. 14/624,340, now U.S. Pat. No. 9,693,870, filed onFeb. 17, 2015, which is a continuation of U.S. application Ser. No.13/937,438, now U.S. Pat. No. 9,072,608, filed on Jul. 9, 2013, which isa continuation of U.S. application Ser. No. 12/782,002, now U.S. Pat.No. 8,500,763, filed on May 18, 2010, which is a divisional of U.S.application Ser. No. 11/055,162, now U.S. Pat. No. 7,744,612, filed onFeb. 10, 2005, which claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application No. 60/543,212 filed on Feb. 10, 2004. Thedisclosures of U.S. application Ser. No. 12/782,002, U.S. applicationSer. No. 11/055,162, and U.S. Provisional Application No. 60/543,212 areincorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates generally to devices and methods formechanically protecting neurovascular structures, and in particular aneural structure located in or about the spine.

Description of the Related Art

Traumatic, inflammatory and degenerative conditions of the spine canlead to severe pain and loss of mobility. According to some studies,back and spine-related musculoskeletal impairment are the leading causesof reduced workplace productivity in the United States. Pain resultingfrom some types of spinal impairment may originate from a variety ofunderlying pathologies and clinical conditions. Some of the most commonsources of pain are related to disc herniation and spinal stenosis.

Disc herniation occurs when some of the disc material found between thevertebrae is displaced and bulges into the spinal canal. Disc herniationoften occurs as the disc material weakens with aging, but may alsoresult from trauma, hereditary factors, or a combination of these andother factors. The resulting pain may be localized to the region ofimpingement or may radiate to the body regions innervated by theimpinged nerve. The common surgical procedure for treating discherniation involves removal of the herniated portion. The surgicalprocedure may also involve removal of most of the disc material and theplacement of a bone graft to promote fusion between the two vertebrae tostabilize that portion of the spine. Surgical screws, rods and spacersmay also be used to fuse the spine, either alone or in conjunction witha bone graft.

Spinal stenosis encompasses a series of conditions where a bony portionof the vertebral column is applying pressure to one or more segments ofthe spinal cord or the nerves that exit from the spinal cord. Thepressure may give rise to pain or numbness in regions of the bodyinnervated by those nerves. One form of spinal stenosis involves anarrowing of the bony canal which contains the nerves or nerve rootsexiting the spinal column. The bony canal or foramen is formed by bonystructures of two adjoining vertebrae of the spine, and may becomenarrow for a variety of reasons. These reasons include but are notlimited to the growth of bone spurs into the foramen, reductions in therelative spacing between two vertebrae from deterioration of thevertebral discs, fractures from trauma or osteoporosis, or frombreakdown of the facet joints where the vertebrae articulate with oneanother. Treatment of spinal stenosis frequently requires surgery toremove a portion of the vertebral bone to create more space for thenerves. This removal of bone may be combined with spine fusion orpartial removal of an intervertebral disc. Other less common conditionsthat may cause nerve impingement include inflammatory disorders of thespine and tumors in the vertebrae.

Notwithstanding the foregoing, there remains a need for improved methodsand devices for treating the spine.

SUMMARY OF THE INVENTION

Devices and methods for protecting the neurovascular structures aboutthe vertebral column are provided. One embodiment of the inventioncomprises a neuroprotective stent or device adapted for placement in anintervertebral foramen of a vertebral column and configured to resistcompression or impingement from surrounding structures or forces. Thestent or device may further comprise a flange or hinge region tofacilitate attachment of the device to the vertebrae or to facilitateinsertion of the device in the foramen, respectively.

One embodiment of the invention comprises a device for treating thespine, the device comprising a tubular body having a first end, a secondend, an abluminal surface, a luminal surface, a lumen, a first edge, asecond edge, and a hinge region, wherein the tubular body is adapted forpositioning within an intervertebral foramen. The device may furthercomprise a flange, and the flange may comprise one or more throughopenings adapted for accepting a bone screw. In some embodiments, thetubular body comprises a material selected from the group consisting ofpolymers, polyetheretherketone (PEEK), polyetherketoneketone (PEKK),polyethylene, fluoropolymers, elastomers, ceramics, zirconia, alumina,silicon nitride; metal(s), titanium, titanium alloy, cobalt chromium,stainless steel, and combinations of these materials. In one embodiment,the hinge region comprises at least one region of reduced wall thicknessof the tubular body.

In another embodiment of the invention, a device for treating the spineis provided, comprising a tubular body, the tubular body comprising afirst end, a second end, an abluminal surface, a luminal surface, alumen, a first edge, and a second edge, wherein the tubular body isadapted for positioning within an intervertebral foramen and wherein thefirst edge and second edge have interlockable configurations. The devicemay further comprise a locking element and wherein the interlockableconfigurations of the first edge and second edge each comprise alignableopenings adapted to accept the locking element.

In one embodiment of the invention, a device for treating the spine isprovided, comprising a tubular body, the tubular body comprising a firstend, a second end, an abluminal surface, a luminal surface, a lumenadapted for accepting a nerve, a first edge, and a second edge, whereinthe tubular body is adapted for positioning within an intervertebralforamen and wherein the tubular body comprises a material selected fromthe group consisting of polymers, polyetheretherketone (PEEK),polyetherketoneketone (PEKK), polyethylene, fluoropolymers, elastomers,ceramics, zirconia, alumina, silicon nitride; metal(s), titanium,titanium alloy, cobalt chromium, stainless steel, and combinations ofthese materials. The tubular body may further comprise a hinge region.In some embodiments, the first edge and second edge have interlockableconfigurations. In one embodiment, the first end of the tubular body hasa flared configuration.

In one embodiment of the invention, another device for treating thespine is provided, comprising a tubular body having a first end, asecond end, an abluminal surface, a luminal surface, a lumen adapted foraccepting a nerve, a first edge, a second edge and a longitudinalopening between the first edge and second edge; and a spacer, whereinthe tubular body is adapted for positioning within an intervertebralforamen. In one embodiment, the spacer has a first groove configured toaccept the first edge of the tubular body and a second groove configuredto accept the second edge of the tubular body.

In another embodiment of the invention, a device for treating the spineis provided, comprising a tubular body having a first end, a second end,an abluminal surface, a luminal surface, a lumen, a first edge and asecond edge, wherein the tubular body is adapted for positioning withinan intervertebral foramen and wherein the tubular body is configured toresist compression forces from spinal structures. The tubular body maybe a stent structure. The spinal structures may comprise anintervertebral disc and/or a vertebra.

One embodiment of the invention comprises a method for treating a spine,the method comprising providing a tubular body having a lumen andadapted for placement within an intervertebral foramen, wherein thetubular body is configured to resist compression forces from spinalstructures and inserting the tubular body into the intervertebralforamen. The method may further comprise providing a spacer, insertingthe spacer into the intervertebral foramen and expanding the tubularbody. In a further embodiment of the invention, the step of providing atubular body comprises providing a stent structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and method of using the invention will be betterunderstood with the following detailed description of embodiments of theinvention, along with the accompanying illustrations, in which:

FIG. 1 is a lateral elevational view of a portion of the vertebralcolumn;

FIG. 2 is a schematic posterior elevational view of two lumbarvertebrae;

FIG. 3 is a schematic superior elevational view of a lumbar vertebra;

FIG. 4 is a schematic lateral elevational view of a portion of thelumbar spine with spinal nerves in the intervertebral foramina;

FIG. 5 is a schematic transverse cross-sectional view of a spine withnerve impingement by a vertebral disc;

FIG. 6 depicts the spine from FIG. 5 with one embodiment of theinvention placed in the intervertebral foramen;

FIG. 7 illustrates one embodiment of the invention comprising acylindrical tubular body;

FIG. 8 is another embodiment of the invention comprising a curvedtubular body;

FIG. 9 is another embodiment of the invention comprising a taperedtubular body;

FIG. 10 is another embodiment of the invention comprising a dual-flaredtubular body;

FIG. 11 depicts another embodiment comprising a tubular body having atriangular outer cross section with a circular lumen;

FIG. 12 is a cross sectional view through one embodiment of theinvention with rounded edges;

FIG. 13 is a cross sectional view through another embodiment of theinvention having complementary edges;

FIG. 14 is a cross sectional view through another embodiment of theinvention having radially outward lipped edges;

FIG. 15 is a cross sectional view through another embodiment of theinvention having interlocking edges;

FIGS. 16A and 16B are oblique elevational views of one embodiment of theinvention with a locking element;

FIG. 17 illustrates one embodiment of the device having a flange;

FIG. 18 depicts one embodiment of the device having a living hinge;

FIGS. 19A and 19B a neuroprotective device with a spacer;

FIG. 20 is a cross sectional view of one embodiment of the inventioncomprising an interlocking spacer and device;

FIG. 21 is a cross sectional view of another embodiment of the inventioncomprising an interlocking spacer and device;

FIGS. 22A and 22B are oblique elevational views of a tapered spacer anda device with a widened gap region; and

FIGS. 23 and 24 depict another embodiment comprising a spiral device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention relates to a treatment for conditions of thespine. In some embodiments of the invention, the treatment allows thepatient to maintain mobility at the treated portion of the spine, unliketraditional spine surgeries or implanted spinal hardware. For example,certain embodiments allow restoration and/or protection of the neuralspace by mechanically alleviating or reducing the pressure exerted ontoneural structures which may reduce or eliminate pain associated withnerve impingement. In some embodiments, the device shields nerves fromcompression by surrounding structures that may cause pain. In oneembodiment, the device prevents the development of postoperativeadhesions or scar tissue between a patient's spinal nerves and otherspinal tissues by providing an intervening barrier. An embodiment of theinvention may also be used to protect other structures in neurovascularbundles, including blood vessels and/or lymphatic ducts.

An embodiment of the invention may also be used as an adjunct todiscectomy procedures. If the disc re-herniates, the device may provideprotection against disc material that may impinge on spinal nerves.

A. Anatomy of the Spine

As shown in FIGS. 1 and 2 , the vertebral column 2 comprises a series ofalternating vertebrae 4 and fibrous discs 6 that provide axial supportand movement to the upper portions of the body. The vertebral column 2typically comprises thirty-three vertebrae 4, with seven cervical(C1-C7), twelve thoracic (T1-T12), five lumbar (L1-15), five fusedsacral (S1-S5) and four fused coccygeal vertebrae 4. Each vertebra 4includes an anterior body 8 and a posterior arch 10. Referring to FIGS.2 and 3 , the posterior arch 10 comprises two pedicles 12 and twolaminae 14 that join posteriorly to form a spinous process 16.Projecting from each side of the posterior arch 10 is a transverse 18,superior 20 and inferior articular process 22. FIG. 3 depicts the spinalcanal 24 that contains the spinal cord (not shown) and is surrounded bythe pedicles 12 and laminae 14. Referring back to FIG. 1 , the pedicles12 of each pair of adjacent vertebrae 4 form an intervertebral foramen26.

FIG. 4 depicts a portion of the vertebral column 2 with spinal nerves 28exiting from the intervertebral foramina 26 formed by the pedicles 12 ofadjacent vertebrae 4. FIG. 5 depicts a transverse cross-sectional viewof the vertebral column 2 through the intervertebral foramina 26 whereinthe vertebral disc 6 has a herniation or bulge 30 posteriorly on oneside and has impinged a spinal nerve root 28 exiting the spinal cord 32.By placing a neuroprotective device 34 in the affected intervertebralforamen 26, as illustrated in FIG. 6 , the device 34 is able to relievepressure exerted on the nerve root 28 by the bulge 30 in the vertebraldisc 6 and may reduce the inflammation and pain associated with nerveimpingement. In addition to protecting the nerve root 28 from dischernations 30 or bone spurs, the device 34 may also protect the nerveroot 28 from postsurgical adhesions or scar tissue that develop fromother spinal surgeries. Postsurgical adhesions or scar tissue may alsocause nerve impingement or nerve irritation.

Referring to FIG. 7 , in one embodiment of the invention, theneuroprotective device 36 comprises a tubular body 38 with a lumen 40and a longitudinal seam or opening 42 along the longitudinal length 44of the tubular body 38. In one embodiment, the tubular body 38 comprisesa stent structure. The tubular body 38 has a first end 46, a second end48, an abluminal surface 50, a luminal surface 52, an outer diameter 54,an inner diameter 56, a first edge 58 and a second edge 60 about thelongitudinal opening 42. In some embodiments, the device 36 has an outerdiameter 54 in the range of about 0.5 mm to about 10 mm, and preferablyabout 3 mm to about 5 mm. The inner diameter 56 of the device 36 is inrange of about 0.4 mm to about 9.9 mm, and preferably about 2 mm toabout 4 mm.

The neuroprotective device 36 may have a generally linear configurationas shown in FIG. 7 , or it may have a non-linear configuration. FIG. 8depicts one embodiment of a non-linear configuration comprising a curvedtubular body 62. A non-linear device may be better fitted to aparticular patient's anatomy than a device 36 with a linearconfiguration.

In some embodiments of the invention, the device 36 has a generallycylindrical shape, as depicted in FIG. 7 , with a generally constantouter diameter 54 and inner diameter 56 along its longitudinal length44. In other embodiments, either or both the outer diameter 54 and theinner diameter 56 of the device 36 can vary along the longitudinallength 44. FIG. 9 depicts one embodiment of the device 64 having atapered outer diameter where the outer diameter 66 at the first end 46is smaller than the outer diameter 68 at the second end 48. Such aconfiguration may facilitate insertion of the device 64 into the foramen26. The inner diameters 70, 72 at the first end 46 and second end 48,respectively, of the device 64 may or may not change proportionatelywith the change in the outer diameters 66, 68. The wall thickness 74 ofthe device need not be constant at any point along the device 64. Insome embodiments of the invention, the wall thickness 74 may be variedto provide augment the structural resistance to directional deformationforces that may affect the protected nerve 28. In another embodiment ofthe invention depicted in FIG. 10 , the tubular body 76 comprises amiddle section 78 having an outer diameter 80 that is less than theouter diameters 82, 84 at the first end 86 and second end 88 of thetubular body 76, respectively. The flared first and second ends 86, 88may assist in stabilizing the position of the tubular body 76 byresisting slippage or displacement of the tubular body 76 out of theforamen 26.

Although the general cross sectional shape of the device 36 depicted inFIG. 7 is a circular C-shape, the cross-sectional shape of the device 36may be any of a variety of shapes, including triangular, oval, square,polygonal, trapezoid or any other shape. The general cross-sectionalshape of the device may vary along the longitudinal length of the deviceand the general cross-sectional shape of the outer diameter and thelumen need not be the same. FIG. 11 depicts a neuroprotective device 90having a linear configuration with a triangular outer cross section 92and a lumen 94 having a circular cross section.

In some embodiments of the invention, the first and second edges 58, 60of the tubular body 38 may be squared or flat, as illustrated in FIG. 7, but in other embodiments, the first and second edges of the tubularbody may have any of a variety of configurations. FIG. 12 depicts across sectional view of one embodiment of the invention wherein thetubular body 96 comprises rounded first and second edges 98, 100. Theconfiguration need not be the same for the first and second edges 98,100 and may also change along the longitudinal length of the tubularbody 96. In some embodiments of the invention, the design and materialsof the tubular body 96 are selected such that the tubular body 96 isconfigured to resist narrowing or closure of the longitudinal seam oropening 42 along the length of the tubular body 96 after implantation.In other embodiments of the invention, the tubular body 96 is configuredto partially bend after implantation such that the first and secondedges 98, 100 of the tubular body 96 contact along at least a portion ofthe longitudinal length of the seam or opening 42.

Referring to FIG. 13 , in some embodiments, the first and second edges102, 104 of the tubular body 106 have complementary shapes that arecapable of forming an interfit to resist further collapse or slippagebetween the first and second edges 102, 104. FIG. 13 illustrates oneembodiment wherein the second edge 104 of the device comprises aY-shaped cross sectional configuration adapted to accept a pointed firstedge 102 of the tubular body 106. The Y-shaped cross section of thesecond edge 104 provides a broader contact surface area to reduce therisk that the first edge 102 may slip past the second edge 104 ascompressive forces causes narrowing or closure of the longitudinalopening 42. One skilled in the art will understand that the first and/orsecond edges 102, 104 of the tubular body 96 may be configured with anyof a variety of complementary configurations to reduce the risk ofslippage between the edges and/or to resist collapse of the tubular body96 generally. In some embodiments, a locking interfit may also be formedby the first and second edges of the tubular body.

In one embodiment of the tubular body 108, shown in FIG. 14 , the firstedge 110 and second edge 112 of the tubular body 108 each comprise a lip114, 116 extending radially outward from the respective edges 110, 112that provide a larger and more stable contact surface area for each edge110, 112. The width of the lips 114, 116 also reduces the risk thateither edge 110, 112 can slip past the other edge 110, 112. The lips114, 116 need not be present along the entire length of the longitudinalopening 42. Optionally, paired openings may be provided in the lips 114,116 to allow the lips 114, 116 to be fastened together with a screw orother fastener.

FIG. 15 depicts one embodiment of the invention comprising aninterlocking complementary fit between the first edge 118 and secondedge 120 of the tubular body 122, with the first edge 118 having a malemember 124 and the second edge 120 having a female receiving site 126for the male member 124.

FIGS. 16A and 16B depict an embodiment of the invention with aninterlockable complementary fit between the first edge 128 and secondedge 130 of the tubular body 132, comprising complementary alternatingprotrusions 134 configured with longitudinally oriented lumens 136 thatalign when the protrusions 134 are in contact with one another. Aseparate locking element 138 may be inserted through the lumen to resistseparation of the edges 128, 130. In a further embodiment of theinvention, the tubular body has two longitudinal portions separated bytwo longitudinal seams, each portion capable of forming an interlockingfit with the other portion.

In some embodiments of the invention, illustrated in FIG. 17 , one ormore flanges 140 may be provided along the abluminal surface 50 of thedevice 36. Each flange 140 may occupy a portion or all of a givencircumference of the tubular body 38. In other embodiments, the flangemay be oriented differently to allow attachment of the device 36 ontothe transverse process or other structure of a vertebra 4. Each flange140 may be located anywhere along the length of the tubular body 38, butis preferably located at the position which provides the expectedinsertion depth of the tubular body 38 into the foramen 26. Thus, theflange 140 may assist the surgeon in positioning the tubular body 38 ina desired location within the foramen 26. In some embodiments, theflange 140 comprises one or more through openings 142 capable ofaccepting a fixation component, such as a bone screw, for attaching thedevice 36 to a bony surface. In some embodiments, the flange 140comprises a material or configuration that provides some malleability toallow the flange 140 to at least partially conform the flange 140 to thebony structure to which it is attached. In some embodiments of theinvention, the flange 140 alone, without any openings, is sufficient tomaintain the device 36 at the desired location.

Referring to FIG. 18 , in some embodiments of the invention, the tubularbody 38 of the device 36 may have one or more regions 144 of reducedwall thickness to facilitate at least partial narrowing or widening ofthe longitudinal opening 42. Typically, the region or regions of reducedwall thickness comprise a full-length longitudinal hinge or groove 144on the abluminal surface 50 and/or luminal surface 52 of the tubularbody 38 that is generally about 180 degrees opposite the position of thelongitudinal opening 42. In other embodiments, however, the region orregions of reduced wall thickness occupy only a portion of thelongitudinal length of the tubular body 38 and/or are located at aposition less about 180 degrees from the longitudinal opening 42 of thetubular body 38. In another embodiment of the invention, the tubularbody 38 comprises a mechanical hinge along the length of the device 36to allow at least partial opening and closing of the longitudinalopening 42.

In another embodiment of the invention, shown in FIGS. 19A and 19B, thedevice 36 further comprises a spacer 146 that may be inserted into thelongitudinal opening 42 of the device 36 to increase size of the lumen40 and provide more space around the nerve root 28. A spacer 146 may beinserted after the device 36 is positioned in the intervertebral foramen26. In one embodiment, the spacer 146 comprises an elongate body 148generally having an H-shaped cross section, an outer height 150, aninter-edge height 152, an inner height 154, a first edge groove 156 anda second edge groove 158, an insertion end 160 and a trailing end 162.The inter-edge height 152 of the spacer 146 determines the separationbetween the edges 58, 60 of the device 36. In some embodiments, theouter height 150 of the elongate body 148 is about equal to the heightof the inner height 154 of the elongate body 148. In other embodiments,the inner height 154 is different from the outer height 150, preferablyhaving a reduced inner height 154 to decrease the amount volume taken bythe spacer 146 in the lumen 40 of the device 36. In some embodiments,either the first edge groove 156 and/or the second edge groove 158 isconfigured with a cross-sectional configuration that is complementary tothe cross sectional shape of the first edge 58 and/or second edge 60 ofthe device 36, respectively, to improve the fit of the spacer 146 to thedevice 36. In some embodiments, the complementary configuration of thedevice 36 and spacer 146 is an interlocking configuration.

FIG. 20 depicts one embodiment of an interlocking configuration of thedevice 36 and spacer 166 comprising protrusions 168 on the abluminalsurface 50 of the device 36 and complementary tracks 170 on the spacer166. FIG. 21 depicts another embodiment where the male member 124 on thefirst edge 118 of the device 122 are capable of forming a snapfit withthe second edge 120 of the device 120, or optionally a snapfit orsliding interlocking fit with a spacer 172 having a female receivingsite 174 complementary to the male member 124 of the first edge 118 ofthe device 122 and a spacer male member 176 that is complementary to thefemale receiving site 126 on the second edge 120 of the device 122. Oneskilled in the art will understand that any of a variety of interlockingconfigurations and sites between the device 122 and spacer 172 may beused for the invention.

Referring to FIGS. 22A and 22B, in some embodiments, the inter-edgeheight 152 of the spacer 146 is tapered at least at the insertion end160 of the spacer 146 to facilitate a gradual separation of the firstand second edges 58, 60 of the device 36 as the spacer 146 is insertedinto the longitudinal seam 42. In one embodiment, at least a portion ofthe longitudinal seam 42 at second end 48 of the device 36 has a taperedgap section 178 to facilitate insertion of the spacer 146 into thelongitudinal seam 42.

FIG. 23 depicts another embodiment of the invention comprising a spiralor coiled neuroprotective device 180 having an insertion end 182 and atrailing end 184 and adapted for insertion into the intervertebralforamen 26. The spacing 186 between each spiral 188 of the device 180 isconfigured to allow the isolated nerve root 28 to pass through thespacing 186 as the device 180 is twisted into the foramen 26. FIG. 24illustrates how the device 180 is inserted into a foramen 26 and overthe nerve root 28. The turn radius of the spirals 188 and the spacing188 between each spiral 188 need not be uniform along the length of thedevice 180. In the preferred embodiment of the invention, the turnradius of the spirals at the insertion end 182 and/or trailing end 184of the device 180 is larger to help maintain the device 180 in theintervertebral foramen 26.

The device 36 may comprise a polymer such as polyetheretherketone(PEEK), polyetherketoneketone (PEKK), or a fluropolymer, an elastomer, aceramic such as zirconia, alumina or silicon nitride, a metal such astitanium, a titanium alloy, cobalt chromium or stainless steel, or acombination of these materials. In one embodiment, the device comprisesa metallic frame embedded in a tubular polymer structure. In embodimentsof the device 36 comprising a non-radioopaque material, radioopaquemarkers may be embedded in or on the device 36 to assist in placement ormonitoring of the device 36 under radiographic visualization. In anotherembodiment, the device 36 may comprise a bioabsorbable or bioresorbablematerial that is known in the art. By selecting a particularconfiguration and material for the tubular body 38, one skilled in theart can adapt the device 36 to have the desired resiliency.

In some embodiments of the invention, the outer surface 50 of the device36 may be further configured to provide one or more characteristics. Inone embodiment, at least a portion of the abluminal surface 50 of thetubular body 38 comprises a porous layer for allowing bone ingrowth intothe device 36. The porous layer may be formed by the application ofsintered beads or plasma sprayed material onto the outer surface of thedevice 36. In other embodiments, the abluminal surface 50 may be lasertreated or mechanically roughened to provide an irregular surface, orformed with protrusions or knurls, to resist sliding contact with bonysurfaces contacting the device 36. In other embodiments, the luminalsurface 50 may be polished or micropolished to facilitate insertion ofthe device into the foramen 26. A polished device 36 may rely on one ormore flanges 118 to secure the device 36 in the foramen 26. The innersurface 52 of the device 36 may be similar treated as the outer surface,but in the preferred embodiment the inner surface 52 is polished ormicropolished to reduce the risk of damage to the neural structureswithin the lumen 40 of the device 36.

The device 36 may also further comprise at least one drug-eluting regionloaded with one or more treatment agents. The treatment agents may beany of a variety of treatment agents known in the art and include butare not limited to anti-bacterial agents, anti-inflammatory agents,anti-proliferative agents

In one embodiment of the device, the intervertebral foramen 26 isaccessed by an open procedure as is known by those with skill in theart. In some embodiments, the vertebrae 4 forming the foramen 26 aredistracted along their longitudinal axis. The neural structure 28 isisolated and the device 36 is passed over the neural structure 28through the longitudinal seam 42 within the intervertebral foramen 26.The placement of the device 36 may be performed in conjunction withorthopedic spine procedures, if any. The device 36 is optionallyattached to one or more vertebrae 4 if the device 36 has at least oneflange 118 with an attachment opening 120. The distraction force, ifany, is removed from the vertebrae 4 and the surgical site is closed.

In another embodiment, the intervertebral foramen 26 is accessed in aminimally invasive manner. In one embodiment, injection of radio-opaquedye is used to identify the vertebrae 4, foramen 26 and neuralstructures 28. In another embodiment, positioning markers may be placedabout the vertebral column 2 to assist in localizing the spinalstructures. The vertebrae 4 forming the foramen 26 are optionallydistracted along their longitudinal axis to enlarge the foramen 26during the procedure. The neural structure 28 is isolated and the device36 is passed over the neural structure 28 through the longitudinalopening 42 within the intervertebral foramen 26 in conjunction with anyother orthopedic spine procedures, if any. The device 36 is optionallyattached to one or more vertebrae 4 if the device 36 has at least oneflange 118 with an attachment opening 120. The distraction force, ifany, is removed from the vertebrae 4 and the surgical site is closed.

While this invention has been particularly shown and described withreferences to embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the scope of the invention. For all ofthe embodiments described above, the steps of the methods need not beperformed sequentially.

What is claimed is:
 1. A method for treating the spine, comprising:providing a spiral body comprising an insertion end, a trailing end, anda lumen, passing an isolated nerve root through a spacing of the spiralbody and into the lumen; and rotating the spiral body to surround theisolated nerve root within an intervertebral foramen.
 2. The method fortreating the spine as in claim 1, wherein the spiral body comprises aconnected series of spirals including a first spiral and a secondspiral, and wherein passing the isolated nerve root through the spacingof the spiral body and into the lumen comprises passing the isolatednerve root through a spacing between the first spiral and the secondspiral and into the lumen.
 3. The method for treating the spine as inclaim 1, wherein the rotation is clockwise.
 4. The method for treatingthe spine as in claim 1, further comprising maintaining the position ofthe spiral body with the trailing end having a larger turn radius. 5.The method for treating the spine as in claim 1, further comprisingmaintaining the position of the spiral body with the leading end havinga larger turn radius.
 6. The method for treating the spine as in claim1, wherein rotating the spiral body comprises rotating the trailing enduntil the trailing end surrounds the isolated nerve root.
 7. The methodfor treating the spine as in claim 1, wherein the spacing is near theinsertion end.
 8. A method for treating the spine, comprising: providinga spiral body comprising an insertion end, a trailing end, and a lumen;and twisting the spiral body to surround an isolated spinal nerve root,wherein a spacing between each spiral of the spiral body allows theisolated spinal nerve root to pass through the spacing as the spiralbody is twisted.
 9. The method for treating the spine as in claim 8,wherein the spiral body comprises a connected series of segmentsincluding a first segment and a second segment, and wherein twisting thespiral body to surround the isolated spinal nerve root comprises passingthe isolated spinal nerve root through a spacing between the firstsegment and the second segment and into the lumen of the spiral body.10. The method for treating the spine as in claim 8, wherein twistingthe spiral body to surround the isolated spinal nerve root furthercomprises twisting the spiral body clockwise.
 11. The method fortreating the spine as in claim 8, further comprising maintaining theposition of the spiral body with the shape of the trailing end.
 12. Themethod for treating the spine as in claim 8, further comprisingmaintaining the position of the spiral body with the shape of theleading end.
 13. The method for treating the spine as in claim 8,wherein twisting the spiral body to surround the isolated spinal nerveroot comprises twisting until the leading end and the trailing endsurround the isolated spinal nerve root.
 14. The method for treating thespine as in claim 8, further comprising positioning the insertion endaround the isolated spinal nerve root before twisting the spiral body tosurround the isolated spinal nerve root.
 15. A method for treating thespine, comprising: providing a coiled body comprising an insertion end,a trailing end, and a plurality of connected segments forming a lumentherein; positioning the insertion end around an isolated spinal nerveroot, wherein the isolated spinal nerve root is passed through a spacingbetween a pair of connected segments; and rotating the coiled body topass the isolated spinal nerve root into the lumen.
 16. The method fortreating the spine as in claim 15, wherein a turn radius of theplurality of connected segments is uniform.
 17. The method for treatingthe spine as in claim 15, wherein the spacing between the plurality ofconnected segments is uniform.
 18. The method for treating the spine asin claim 15, wherein a turn radius at the trailing end is larger to helpmaintain the coiled body in an intervertebral foramen.
 19. The methodfor treating the spine as in claim 15, wherein a turn radius at theleading end is larger to help maintain the coiled body in anintervertebral foramen.
 20. The method for treating the spine as inclaim 15, further comprising rotating the coiled body until the coiledbody surrounds the isolated spinal nerve root.